import java.util.Random;

/**
 * 912. 排序数组
 * https://leetcode.cn/problems/sort-an-array/description/
 */
class Solution {
    public int[] sortArray(int[] nums) {
        qsort(nums, 0, nums.length - 1);
        return nums;
    }
    public void qsort(int[] nums, int l, int r) {
        if(l >= r) return;

        int key = nums[new Random().nextInt(r - l + 1) + l];
        int left = l - 1, right = r + 1, i = l;
        while(i < right) {
            if(nums[i] < key) swap(nums, ++left, i++);
            else if(nums[i] == key) i++;
            else swap(nums, --right, i);
        }
        //[l, left],[left+1, right-1],[right, r]
        qsort(nums, l, left);
        qsort(nums, right, r);
    }
    public void swap(int[] nums, int i, int j) {
        int t = nums[i];
        nums[i] = nums[j];
        nums[j] = t;
    }
}